In which I present a list of different types of comedy sketch, because why not, and also because if you’re writing a sketch, maybe this will help.
(Note: this list is not exhaustive, although it exhausted me.)

INVERSION

Up is down, black is white, dogs and cats living together… Inversion sketches present a character or situation behaving the opposite to what we might expect. For characters, this will often be an inversion of status: a childish judge, an over-emotional nightclub bouncer, a Tory MP with a human heart (satire).

MISDIRECTION / PULL BACK AND REVEAL

This is the sketch equivalent of the “…and then I got off the bus” punchline. Best kept short. An example would be a CSI-type set up, with experts gathered around an unseen “corpse” talking about signs of burning, teeth marks, spatter patterns etc – THEY’RE ONLY LOOKING AT A PIZZA! LOL!

EXAGGERATION

An exaggeration sketch will take a recognisable situation and distort it via exaggeration. Possibly I didn’t need to write that.

DISPLACEMENT

A sketch in which we take a character and put them in a completely inappropriate/unexpected environment. Prince Philip on Pointless, Bear Grylls on a perfume counter (ooh, that’s good, I might use that).

ANACHRONISM

A sketch in which characters/situations shouldn’t be together as they belong in different eras – Henry VIII having to deal with a chugger, or Hitler signing on (don’t do this one). Or Armstrong and Miller’s WW2 Fighter Pilots – the look is one era, the dialogue is another. Random.

THE ESCALATOR

Escalator sketches start off sensible and then ramp up the absurdity until they end up being completely silly/surreal. See Python’s Four Yorkshiremen boasting who had the worst childhood, or the dirty knife sketch.

PARODY

See Scary Movie. Or rather don’t. See French and Saunders’ movie parody sketches, or anything John Culshaw does. Or, again, don’t see those. Let’s avoid parody.

THE LIST / REPETITION SKETCH

Pick a topic, load up thesaurus.com or Wikipedia, you’re away.

I’M WITH STUPID

There’s this normal character, right, and then there’s this not-normal character. And the normal character reacts to the not-normal one. A classic sketch ensues.

REFRAMING

A sketch which relocates an activity. General election in Narnia.

THE WORLD’S WORST

Think of a job or activity. Think of the very worst person who could be doing it. Write that.

X-RAY / HANG A LANTERN SKETCH

Highlighting the absurdity of a character or situation by having the characters point it all out. Can also include “meta sketches” – sketches which are about themselves. Clever.

That’s probably enough taxonomising of comedy for now. But if you can think of any other categories, or better examples than the ones I’ve got, let me know and I’ll see about updating the list.